The MPLS Traffic Engineering (TE) Automatic Bandwidth Adjustment for TE Tunnels feature provides the means to automatically adjust the bandwidth allocation for traffic engineering tunnels based on their measured traffic load. The configured bandwidth in the running configuration is changed due to the automatic bandwidth behavior.

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The automatic bandwidth adjustment feature treats each tunnel for which it has been enabled independently. That is, it adjusts the bandwidth for each such tunnel according to the adjustment frequency configured for the tunnel and the sampled output rate for the tunnel since the last adjustment without regard for any adjustments previously made or pending for other tunnels.

If a tunnel is brought down to calculate a new label switched path (LSP) because the LSP is not operational, the configured bandwidth is not saved. If the router is reloaded, the last saved automatic bandwidth value is used.

MPLS traffic engineering supports only a single IGP process/instance. Multiple IGP processes/instances are not supported and MPLS traffic engineering should not be configured in more than one IGP process/instance.

MPLS TE Automatic Bandwidth Adjustment for TE Tunnels Overview

Traffic engineering autobandwidth samples the average output rate for each tunnel marked for automatic bandwidth adjustment. For each marked tunnel, the feature periodically (for example, once per day) adjusts the tunnel’s allocated bandwidth to be the largest sample for the tunnel since the last adjustment.

The frequency with which tunnel bandwidth is adjusted and the allowable range of adjustments is configurable on a per-tunnel basis. In addition, the sampling interval and the interval over which to average tunnel traffic to obtain the average output rate is user-configurable on a per-tunnel basis.

MPLS TE Automatic Bandwidth Adjustment for TE Tunnels Benefits

The automatic bandwidth feature allows you to configure and monitor the bandwidth for MPLS TE tunnels. If automatic bandwidth is configured for a tunnel, TE automatically adjusts the tunnel’s bandwidth.

The value for the process-id argument is an internally used identification parameter for an OSPF routing process. It is locally assigned and can be any positive integer. Assign a unique value for each OSPF routing process.

Step 4

mplstraffic-engareanumber

Example:

Router(config-router)# mpls traffic-eng area 0

Turns on MPLS TE for the indicated OSPF area.

Step 5

mplstraffic-engrouter-idloopback0

Example:

Router(config-router)# mpls traffic-eng router-id loopback0

Specifies that the TE router identifier for the node is the IP address associated with interface loopback0.

Step 6

exit

Example:

Router(config-router)# exit

Exits to global configuration mode.

Step 7

exit

Example:

Router(config)# exit

Exits to privileged EXEC mode.

Configuring Bandwidth on Each Link That a Tunnel Crosses

SUMMARY STEPS

1.enable

2.configureterminal

3.interfacetypenumber

4.mplstraffic-engtunnels

5.iprsvpbandwidth [interface-kbps] [single-flow-kbps] [sub-poolkbps]

6.exit

7.exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2

configureterminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interfacetypenumber

Example:

Router(config)# interface FastEthernet 0/0/0

Configures an interface type and enters interface configuration mode.

Step 4

mplstraffic-engtunnels

Example:

Router(config-if)# mpls traffic-eng tunnels

Enables MPLS TE tunnels on an interface.

Step 5

iprsvpbandwidth [interface-kbps] [single-flow-kbps] [sub-poolkbps]

Example:

Router(config-if)# ip rsvp bandwidth 1000 100

Enables Resource Reservation Protocol (RSVP) for IP on an interface.

The interface-kbps argument specifies the maximum amount of bandwidth (in kbps) that may be allocated by RSVP flows. The range is from 1 to 10000000.

The single-flow-kbpsargument is the maximum amount of bandwidth, in kbps, that may be allocated to a single flow. The range is from 1 to 10000000.

Step 6

exit

Example:

Router(config-if)# exit

Exits to global configuration mode.

Step 7

exit

Example:

Router(config)# exit

Exits to privileged EXEC mode.

Configuring an MPLS Traffic Engineering Tunnel

To configure an MPLS TE tunnel, perform the following task. The MPLS TE tunnel has two path setup options: a preferred explicit path and a backup dynamic path.

Note

The configuration applies only to the TE head-end node. The configuration applies to all nodes and interfaces in the network.

Gives the tunnel interface an IP address that is the same as that of interface Loopback0.

An MPLS TE tunnel interface should be unnumbered because it represents a unidirectional link.

Note

This command is not effective until Lookback0 has been configured with an IP address.

Step 5

tunneldestinationip-address

Example:

Router(config-if)# tunnel destination 10.3.3.3

Specifies the destination for a tunnel.

The destination must be the MPLS TE router ID of the destination device.

Step 6

tunnelmodemplstraffic-eng

Example:

Router(config-if)# tunnel mode mpls traffic-eng

Sets the encapsulation mode of the tunnel to MPLS TE.

Step 7

tunnelmplstraffic-engbandwidthbandwidth

Example:

Router(config-if)# tunnel mpls traffic-eng bandwidth 250

Configures the bandwidth for the MPLS TE tunnel.

The bandwidth argument is the bandwidth, in kilobits per second, set for the MPLS TE tunnel. The range is from 1 to 4294967295. The default is 0.

If automatic bandwidth is configured for the tunnel, the tunnelmplstraffic-engbandwidth command configures the initial tunnel bandwidth, which will be adjusted by the autobandwidth mechanism.

Note

If you configure a tunnel’s bandwidth with the tunnelmplstraffic-engbandwidth command and the minimum amount of automatic bandwidth with the tunnelmplstraffic-engauto-bwcommand, the minimum amount of automatic bandwidth adjustment is the lower of those two configured values.

Configures the tunnel to use a named IP explicit path or a path dynamically calculated from the TE topology database.

A dynamic path is used if an explicit path is currently unavailable.

Step 9

exit

Example:

Router(config-if)# exit

Exits to global configuration mode.

Step 10

exit

Example:

Router(config)# exit

Exits to privileged EXEC mode.

Troubleshooting Tips

Each tunnelmplstraffic-engauto-bw command supersedes the previous one. Therefore, if you want to specify multiple options for a tunnel, you must specify them all in a single tunnelmplstraffic-engauto-bw command.

Enabling Automatic Bandwidth Adjustment on a Platform

To enable automatic bandwidth adjustment on a platform and initiate sampling the output rate for tunnels configured for bandwidth adjustment, perform the following task.

Note

This task is applicable only to the TE head-end router. The configuration applies to all locally-configured TE head-end interfaces.

SUMMARY STEPS

1.enable

2.configureterminal

3.mplstraffic-engauto-bwtimers [frequencyseconds]

4.nomplstraffic-engauto-bwtimers

5.exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2

configureterminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

mplstraffic-engauto-bwtimers [frequencyseconds]

Example:

Router(config)# mpls traffic-eng auto-bw timers frequency 300

Enables automatic bandwidth adjustment on a platform and begins sampling the output rate for tunnels that have been configured for automatic bandwidth adjustment.

The frequency keyword specifies the interval, in seconds, for sampling the output rate of each tunnel configured for automatic bandwidth. The range is 1 through 604800. The recommended value is 300.

Step 4

nomplstraffic-engauto-bwtimers

Example:

Router(config)# no mpls traffic-eng auto-bw timers

(Optional) Disables automatic bandwidth adjustment on a platform.

Use the no version of the command, whichterminates output rate sampling and bandwidth adjustment for tunnels. In addition, the no form of the command restores the configured bandwidth for each tunnel where the configured bandwidth is determined as follows:

If the tunnel bandwidth was explicitly configured via the tunnelmplstraffic-engbandwidth command after the running configuration was written to the startup configuration, the configured bandwidth is the bandwidth specified by that command.

Otherwise, the configured bandwidth is the bandwidth specified for the tunnel in the startup configuration.

The examples omit some configuration required for MPLS TE, such as the required RSVP and Interior Gateway Protocol (IGP) (IS-IS or OSPF) configuration, because the purpose of these examples is to illustrate the configuration for automatic bandwidth adjustment.

Example: Configuring MPLS Traffic Engineering Automatic Bandwidth

The following example shows how to use the
mplstraffic-engauto-bwtimers command to enable automatic bandwidth adjustment for Router 1. The command specifies that the output rate is to be sampled every 10 minutes for tunnels configured for automatic bandwidth adjustment.

Example: Tunnel Configuration for Automatic Bandwidth

The following example shows how to use the
tunnelmplstraffic-engauto-bw command to enable automatic bandwidth adjustment for Tunnel 1. The command specifies a maximum allowable bandwidth of 2000 kbps, a minimum allowable bandwidth of 1000 kbps, and that the default automatic bandwidth adjustment frequency of once a day be used.

RFCs

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified.

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The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to
www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

The MPLS Traffic Engineering Automatic Bandwidth Adjustment for TE Tunnels feature provides the means to automatically adjust the bandwidth allocation for traffic engineering tunnels based on their measured traffic load. The configured bandwidth in the running configuration is changed due to the automatic bandwidth behavior.

In Cisco IOS Release 12.2(33)SRE, this feature was introduced.

In Cisco IOS XE Release 3.8S, support was added for the Cisco ISR
4400 Series Routers.

In Cisco IOS XE Release 3.9S, support was added for the Cisco CSR 1000V.